Regulating system



Dec. 25, 1934. w. K FLEWNG 1,985,635

REGULAT ING SYSTEM Original Filed April 28, 1928 111+: be M n 2, HQ 4' vI? 10 f9 F76 J W T b5 1: 7 1 J INVENTOR. h gflz c A TTORNE Y.

Patented Dec. 25, 1934 UNITED STATES 3,985,635 REGULATING SYSTEM WilfredK. Fleming,

Qambridge, Mass, assignor,

by mesne assignments, to Raytheon Manufacturing Company, of DelawareNewton, Mesa, a corporation Application April .28, 31928,. Serial No.273,719

Renewed Octoher 19,

8 Claims.

My invention relates to an electrical regulating system and morespecifically to a power transformation system whereby variations ofinput voltage over a wide range of limits do not affect the voltageoutput in any substantial degree.

The recent developments of radio receiving systems have resulted in ademand for means for supplying the filament and plate circuits of vacuumtubes from the ordinary house current mains. As is well known, thethermionic tubes used in such sets require that the power delivered tothem be of substantially constant and invariable voltage. distributionof alternating current for domestic purposes, it is practicallyimpossible for the voltage of the house circuit to be constantthroughout the day or to be equal to the voltage otthe circuit inanother house. The load variations through the day result in linevariations. The 2 position of the particular house circuit with respectto the supply transformer, as well as the position of the supplytransformer with respect to the high tension mains, results in a voltagevariation which not only occurs through the day in one particular spot,but which also occurs among a number of spots at one particular time Theordinary means for translating the alterhating current of the mains intosubstantially direct current for use in a radio receiving 39 comprisesatransformer, a rectifier in secondary circuit, and means for filteringout and smooth= ing out the ripples in the rectified current. It willreadily be seen that as the line voltage va-= rice, the final rectifiedvoltage will vary and thi less compensating means at the radio receivingset are used, the tubes will be operated more or less haphazardly. Suchhaphazard tube operation is very bad on the life of the tube. It thefilaments of the tubes are operated in such a manner, they will beburned out or stripped of their coating depending upon whether thefilement is overloaded or underloaded. If the plate circuit varies toomuch, a great plate voltage over=- load-will strip the filament orparalyze the tube.

My invention aims at overcoming the variations in secondary voltage,irrespective of how the prl-= many line voltage may vary withinreasonablywide limits. Although I have described my in= vention withreference to a vacuum tube supply system, it is to be clearly understoodthat my invention is independent of this and may be used wherever aconstant voltage which is to be obtained from a variable voltage isrequired. Although the variations may be fast, it will readily beunderstood that the variations might just as well be over a period ofdays or even weeks and in fact, the supply voltage need not necessarilyvary at all and can very well be dilferent from what is ordinarily takenas the average.

In the broader aspects of the invention, the

Under the present methods of voltage supply is divided up into twovector quantitles. The magnitude of one of these vector quantities iskept substantially constant and this quantity is the one that isactually used. The other vector quantity is allowed to vary although itsmagnitude, too, may be kept constant. In either case, this second vectorquantity, whether variable or constant, may be used or discarded. Theangle between the two vectors is allowed to vary. in this way, thesupply voltage which, of course, represents the resultant vector isbroken up into the above two vectors. The variable resultant has as itscounterpart in the components, the variable phase angle and perhaps onevariable vector, the other remaining substantially constant.

y invent n is an improvement on the inventhe subject of my applicationentitled Regulating systein, Serial No. 267,402, filed April 1928, andassigned to the same assignee this case.

In the application mentioned, the invention broadly comprises a systemfor accomplishing substantially same results as my invention does. Themeans for accomplishing coniprises in general a transformer, the primaryof which in series with a reactance is either predominantly capacitativeor inductive.

the

also an inductance as a choke or transformer used in connection Thischoke or transreactance is capacitative, then there is former nae alarge capacity used with it so that combination is capacitative. Thesubstantial constancy of voltage may be obtained either at the urinalsor the inductive or capacitative part of .e system. In any event, theinductance which e either a choke or a transformer, which is of thecapacitative portion of the system, i operated preferably at the upperbend or the magnetization curve. This is done in order to take advantageof the very large variation of inductance with small variation oiimpressed voltage. 1

The capacity may be assumed to be constant for all practical purposes.The result is, therefore, that capacitative portion of the system asmall change in voltage across the terminals oil that portion of thesystem will result in a current change which will result in a or thevalue of inductance and hence the effec tive react'ance ofthecapacitative portion of the system is materially changed, thusresulting in a phase displacement between current and voltage.

Of course it is to be understood that the choke might be used inthe'inductive portion of the system and the transformer be part of thecapacitative portion or" the system.

' By actual measurement the voltage across each portion of the systemhas been measured and since the actual numerical values do not greatchange by operating as the cross sections of the other two legs.

differ very much with the variation in line voltage, the only logicalconclusion is that the phase angle is changed. The inductance of thecapacitative portion of the system need not of necessity be operated atthat portion of the curve and may actually be operated on any non-linearpart of the magnetization curve, but best-results are obtained stated.The inductive portion of the system may or may not be. operated at thesame portion of magnetization curve.

To make a device embodying a regulating system as above described,commercially practical, it must be compact, must have as little materialtherein as possible and be efficient. In general, my improvementconsists in winding all the necessary coils on one core. I also make useof an auto transformer, rather than a transformer with two separatewindings to save materials and space. In this way, the wire of theautotransformer carries both primary and secondary currents, which ofcourse, are in opposition and thus less copper is required than wouldordinarily be the case. Since the core is operated at a high magneticintensity by at least one of the inductive elements of the system, itcanreadily be seen that there will be considerable heat losses in the corefrom that fact alone. By combinin all inductance elements on one core, Ihave applied the same heat losses to a greater massthat is, a greatercore in this instance-withthe result that the entire core will run muchcooler,

especially at high loads.

as is well known, the-primary and secondary currents in anautptransformer are approximately 180 out of phase with each other. Theresult will be that that portion of the wire which carries bothsecondary and primary currents will only have the difference between thecurrents.- This means that with less current flowing through aconsiderable portion of the transformer, the resistance losses which aretransformed into heat will be much less than would be the case werethere two separate coils. Hence, by my improvement in combining all theinductance elements on one core, I have reduced the current losses andthe heating effect therefrom and have distributed the heat losses in themagnetic core over a much greater mass of material.

In additionto the above-what might be termed technical advantages-thedevice as a whole becomes much more compact, requires less material andis considerably cheaper than the system of the application aboverReferring to the above in general, I carry out my invention by providinga three legged core, the central leg'having a cross sectionapproximately equal to the sum of The outside legs may be ofsubstantially equal cross section but need not be so if not desirable.On one leg, I wind a coil which is tapped at an intermediate portionthereof. The entire coil represents the secondary of the autotransformerwhile a smaller portion thereof comprises the primary of theautotransformen. On the other leg of the core, I provide primary andsecondary coils of a transformer. The first coil and primary of thetransformer are connected in series and have the line current flowingthrough them. By suitably connecting a capacity in the circuit, I makeone of the inductance elements part of a capacitative load in which theinductance changes greatly with a comparatively small change of' appliedpotential.

Referring to the drawing;

Figure 1. shows one form of my invention,

0 to the outer end of '8 and end of the primary 4.

I a filter 16 shown here Figure 2 is a modification,

Figure 3 is a diagrammatic vention,

Figures 4 and 5 are to Figure 3,

Figure 6 is a vector diagram of the resultants obtained from Figures 4and 5.

Referring to Figure 1, there is shown the three legged core 30 havingthe end legs 31 and 32 preferably of substantially equal cross sectionand the central leg 33 equal to the cross sections of the other two. Onleg 31 is wound a coil which is tapped at 8, forming coils 2 and 3. L 0nthe other leg are wound primary 4 and secondary 10 of a transformer.Conductor 9 connects outer end of coil 2 to the primary 4. The other endof primary 4 is connected through a condenser coil 8 on coil 1 is moreor less related to the capacity of condenser C and in general, thegreater the capacity of condenser C, the nearer to the condenser tap8-approaches. Across tap 8 and outer end of coil 3 is connected 9.variable resistance R. The line supply 6 and 'I is connected to tap Thesecondary 10 of the transformer, as is usual, has a center lead 11 andtwo end leads 12 and 13 for rectification purposes. The two end leadsare connected to any suitable rectifying device 14 and finally go out tolead 15. lead of the rectified current circuit. If desired, ascomprising a plurality of-shunt condensersand series inductances, may beconnected to smooth out the current impulses.

The resistance R is made variable so that the amount of current flowingthrough coil 3 may be regulated and thereby insure the proper operationof the device.

, The line current goes from lead 6 to tap 8 showing of the invectordiagrams referring through coil 2 which forms primary 2 of theautotransformer and then to the primary 4 of the transformer and then tothe other side '1 of the line. The secondary of the autotransformercomprises coils 2 and 3. The condenser C combined with the coil 3 of the'autotransformer makes the autotransformer load capacitative withrespect to the coil 3 and hence aids in regulating the system.

If desired, other secondaries 18 and 19 may be added on core 32 toprovide filament supply for tubes or other purposes. 4

Referring to Figure 2, we have substantially the same elements andconnections except that condenser C and resistance R. are connectedacross the entire secondary 2 and 3 of the autotransformer.

Referring to Figure 3 two'tr'ansformers Tand '1' are shown. T hascapacitance C across its secondary which operates in such a way that theentire transformer load becomes capacitative rather than inductive; R1and R2 represent the loads. V0 and Vi. each represent the capacitatlveand inductive load voltages in series ac the line.

In the vector diagrams, Figures 4 and 5, Figure 4 represents theinductive portion of the system,

namely T1 and its circuits while Figure 5 represents the capacitativeportion of the entire loadthat is, transformer T and its circuits. 1;represents the line current. Along vector'Vr. may be laid of! vectors Iaand Ian. In represents the load current while 111+: represents thecurrent losses due to hysteresis and eddy currents.

At right angles to the current vector, is ve t The central lead 11 isthe other 3. The position of tap menses I which represents themagnetizing component of the current at right angles to the primaryvoltage. The resultant IQ of the two vectors law and 1., represents theno load operating current. The vector Ip, which is the resultant of Inand I0, represents the current going through the primary of T1. In caseT1 were a choke this current would, of course, be the current goingthrough the choke. As can be seen, the angle between V1. and 11represents the lagging current in T1.

Referring to Figure 5, V0, 1'1: and l' n are laid oil? in similarmanner. The resultant lo is obtained in the same manner as in Figure 4.At right angles to V and opposite in direction to I", is laid off lcwhich is the capacitative leading current. Subtracting I'., from andthen combining I'i-H-E with this difierence vector, we obtain vector Is.Combining this vector with the load current I'n, we finally obtain theresultant Ip which, as. above, represents the current through theprimary of the loadin this caseof transformer T. It should be noted thatsince T and T1 have their primaries in series, IP will be the same inboth instances and, therefore, vectors Is in Figures 4 and 5 are equalto each other. Figure 6 is a composite of both resultants of Figures 4and 5. Taking vectorVp and laying Ip along in the same direction, we mayobtain components V1. and V0 from the original VP. It should be notedthat the supply line is assumed to have substantially unity p veerfactor since Ip and Vp are in the same dir ction; Vc has been transposedabout VP so as to close the triangle. I

Assume that VP varies. It is readily seen that this variation may betaken up in any one of three ways. The sides of the triangle V1. and V0may both remain substantially constant while their angles with respectto each other and to the base VP may change. This, of course, is onlytrue within certain limits. In addition, the lengths of the two sidesV1. and V0, as well as their angles, may change to meet the changinglength of VP. A third way is for the angles to remain the same as VPchanges, while the lengths of VL and V0 change. It is also possible tohave only one side of V1. or Vc change as well as the angles when baseVP changes. The dotted lines V1. and V'o show a variation of base V1.V1. remains substantially constant while 0 varies as well as Vc.

Thus it can be seen that though base VP varies considerably, still V1.and V0 do not vary much, VL swinging and describing an arc of a circle.In my system, Ikeep at least one of the sides, preferably vn'cons'tantand allow Vc and the corresponding angles to vary as VP changes. I can,of course, keep both VL and V0 constant and merely allow the angles tovary, but this method is not as desirable from a commercial point ofview as only'keeping one side constant.

Thus it will be seen that I have devised a system which will regulate towithin close limits for variations of or departures from standardvoltages. Furthermore, the system may be embodied in an apparatus whichis cheap, and requires a minimum of parts and material and operates witha minimum of losses.

I claim:

1. A regulating system comprising a transformer having a primary andsecondary, an impedance in series with the primary, said impedancehaving inductance, and a condenser associated with the impedance, thesystem therebyrib providing means for operating the inductance of one ofthe elements with which the condenser is associated so that a, smallchange of voltage results in a great change in the value of theinductance, all the magnetic elements having a common core.

2. A regulating system comprising a plurality of inductances in series,and a condenser in parallel with one of said inductances, the systemthereby providing means for operating at least one of said inductancesso that its value changes greatly comparedv to voltage changes, saidinductances having a common core.

3. A regulating system comprising a plurality of inductances in series,at least one of said inductances being a transformer, and a condenser inparallel with at least one of said inductances, the system therebyproviding means for operating at least one of said inductances so thatits value changes greatly compared to voltage changes, one of saidinductances being an autotransformer.

4. A constant current supply system comprising a. transformer having aprimary and secondary, an inductance in series with the primary, saidtransformer and inductance having a common core, and a condenserassociated with at least one of the series connected elements, thesystem thereby providing means for operating the element with which saidcondenser is associated so that small voltage variations result in largeinductance variations.

5. An alternating current regulating system adapted to supply a.substantially constant alternating voltage from a line in which voltagefluctuations occur comprising means for breaking up the line voltageinto a plurality of portions, means for causing a. phase displacement ofsaid voltages andfor causing a variation of said phase displacement asthe line voltage varies, and means causing any further line voltagevariations to be restricted to one of the voltage portions, all of saidmeans comprising a plurality of inductances on a common core.

=3. A regulating system, comprising a plurality of inductances in seriesand a condenser associated with one of said inductances, at least one ofsaid inductances being so operated that its value changes greatlycompared to voltage changes, all of said inductances having a commonmagnetic core.

'7. A regulating system, comprising a network consisting of a pluralityof inductive and reactive lmpedances in series, all of said inductiveimpedances having a common magnetic core, a source of alternatingpotential connected to two spaced points in said network, at least oneof said reactive impedances being so operated that its value changesgreatly compared to voltage changes impressed thereon.

8. An alternating current regulating system adapted to supply asubstantially constant alternating voltage from a line in which voltagefluctuations occur, comprising means for breaking up the line voltageinto a plurality of components, means for causing a phase displacementbetween said components, and means for causing a variation of said phasedisplacement as the line voltage varies, said means being so designedthat said variations in line voltage produce variations in magnitude ofbut one of said components, each of 'said means including an inductanceand all of said inductances being provided with a common magnetic core.

WILFRED K. FLEMING.

